<!DOCTYPE html>
<html lang="en">
    <head>
        <meta charset="UTF-8">
        <title>今天的周数</title>
    </head>
    <body>
        <h3>今天是开学以来第几周，星期几</h3>
        <p id = "today"></p>
        <script>
            let today = new Date();
            let start = new Date("02/06/2023");
            let week = Math.floor((today.getTime()/(1000*3600*24)-start.getTime()/(1000*3600*24))/7);
            let ord = today.getDay();
            let tt = "";
            switch (ord) {
                case 0:
                    tt = "星期日";
                    break;
                case 1:
                    tt = "星期一";
                    break;
                case 2:
                    tt = "星期二";
                    break;
                case 3:
                    tt = "星期三";
                    break;
                case 4:
                    tt = "星期四";
                    break;
                case 5:
                    tt = "星期五";
                    break;
                case 6:
                    tt = "星期六";
                    break;
            }
            document.getElementById('today').innerHTML = "今天是开学第"+(week+1)+"周,"+tt;
        </script>
    </body>
</html>